Mars Contains Organics After All, New Research Says

Friday

Sep 3, 2010 at 10:32 PM

Thirty-four years after NASA's Viking missions to Mars sent back results interpreted to mean there was no organic material - and consequently no life - on the planet, new research has concluded that organic material was found after all.

By MARC KAUFMANTHE WASHINGTON POST

Thirty-four years after NASA's Viking missions to Mars sent back results interpreted to mean there was no organic material - and consequently no life - on the planet, new research has concluded that organic material was found after all.

The finding does not bring scientists closer to discovering life on Mars, researchers say, but it does open the door to a greater likelihood that life exists, or once existed, on the planet.

"We can now say there is organic material on Mars, and that the Viking organics experiment that didn't find any had most likely destroyed what was there during the testing," said Rafael Navarro-Gonzalez, of the National Autonomous University of Mexico.

'FOLLOW THE ORGANICS,' NOT WATER

"For decades, NASA's mantra for Mars was 'follow the water' in the search for life, and we know today that water has been all over the planet," he said. "Now the motto is 'follow the organics' in the search for life."

The original 1976 finding of "no organics" was controversial from the start, because organic matter - complex carbons with oxygen and hydrogen, which are the basis of life on Earth - is known to fall on Mars, as onto Earth and elsewhere, all the time. Certain kinds of meteorites are rich in organics, as is the interstellar dust that falls from deep space and blankets planets.

The new results, published in the Journal of Geophysical Research-Planets, flow directly from a discovery made by NASA's Phoenix lander in 2008.

Mary Voytek, senior scientist for astrobiology at NASA, said that the findings demonstrate the ever-present risk of reaching "false negatives" in space based on limitations of the equipment used and of the scientists' understanding of conditions beyond Earth.

She said that the research does not fully knock down the original "no organics" conclusion because the new experiment was done using desert soil from Earth, which might behave differently from seemingly similar Martian dirt. But she said it does put another "significant chink" in the no-organics position.

UNEXPECTED COMPOUND

The new research found a unexpected and unusual compound to be widespread at its landing site on northern Mars.

The discovery of the highly reactive chemical perchlorate led NASA's Christopher McKay, an astrobiologist at the Ames Research Center, and Navarro-Gonzalez to test whether the perchlorate had skewed the Viking results that showed no sign of organic material on Mars.

The two researchers combined magnesium perchlorate with soil from the most Mars-like environment on Earth - the Atacama Desert in Chile - and heated the sample in the same way that it was heated by Viking instruments on Mars.

They found that the small amount of organic material known to be in the Atacama soil was detectable when mixed with the perchlorate low temperatures, but was broken up into water and carbon dioxide when heated alongside the perchlorate. The Viking experiment had heated the sample to a similarly high temperature.

In addition, the researchers found evidence of the organic compound chloromethane after they heated the Atacama soil with perchlorate. That compound had been detected during the organics experiments at both Viking landing sites, but had been written off as a contaminant from Earth since it is in cleaning fluids.

Navarro-Gonzalez said his team ran the experiment many times and always produced some form of chloromethane - leading to the conclusion that it was being formed by the combining of the perchlorate with some form of organic Mars material.

"The big lesson here, and the great importance of this finding, is that we have to know what we're looking for and how we can find it," Voytek said. "It shows that we could actually uncover life on Mars and not know it."

That is what some think already happened on Mars. A life-detection experiment on both Viking landers gave a positive signal that something in the soil was metabolizing a food source introduced, and a negative signal in the control experiment. The principle investigator of that experiment, Gilbert Levin, has argued for more than 30 years that Viking did, indeed, find life.